[Lowfer] AMRAD LF UpVerter

[Peter Barick]

LowFERs

Frank Gentges' follow-up to the his Active Antenna last  September is
in the April QST. It's a LF Upconverter and, as with the Act-Ant, it
seems to be designed by the "Taco 0Boys" from "Tippy's" dinner. Seems
those boys get charged up plenty there. Oh, the article is co-authored
by Steve Retzlaff.

This effort is modularized: A LF lowpass filter board, the mixer board
and a power board, all of which, the 3 boards, are available for $12
from FAR. Nice thing about this is one can select it all or just some of
the components. Frank also thought ahead and allows either a xtal or alt
DIP osc. Another of Frank's thoughts is rearranging the components as a
transverter for a HF rig. That may be handy in due time for a possible
new band plan.

The bandpass filter is tunable using readily accessible vendor parts
and--warning!--three torides to wind. :=}

The heart of it is the converting mixer, which is all contained in a
common CMOS IC. The authors explain the reasoning for selecting this
over, say, a DBM design, as used in the Tim Brannon converter (see the
LWCA site).

While most LowFERs don't seem to use converters, many use their HF rigs
having LF rx ability and are stable or they may use a rx, e.g., a SLVM
or the R75, this xvtr is an option for some who may want to extend the
range of whatever they now have. Or, as noted, one can build just the
passive filter to clean up a local image problem.

Other thoughts on this project?

Peter